This invention relates generally to signal splitter and balun devices and is particularly directed to a device for coupling separate balanced UHF and VHF antenna leads to a single input terminal of a television receiver.
Television receivers typically include two sets of input terminals, one for receiving UHF signals and the other for receiving VHF signals. Each set of input terminals is coupled to a respective receiving antenna. The introduction of the integrated antenna capable of receiving both UHF and VHF signals gave rise to the requirement for a coupler capable of providing UHF and VHF signals from a single pair of twin leads to two sets of input terminals on the television receiver. A similar device incorporating a coaxial input terminal has found use in cable television (CATV) systems for connecting a single coaxial "drop" cable to separate pairs of UHF and VHF television receiver antenna terminals for UHF, VHF and CATV viewing. Because this type of single input-dual output coupler is not generally provided with the television receiver but rather is sold separately, it does not have to meet line voltage (120 VAC, 60 Hz) isolation safety criteria generally applicable to consumer appliances. In addition, these antenna couplers are typically provided with a large number of circuit components which substantially increases their cost.
Because of the use of a single coaxial cable in CATV systems and the increasing program selection and availability of CATV systems, television receiver manufacturers are considering, and in some cases implementing, plans for producing receivers with a single input signal terminal. See, for example, commonly assigned application Ser. No. 401,449, filed July 26, 1982, and entitled "Switching Diplexer for Single Antenna Input Television Receivers". The single input terminal approach not only reduces television receiver cost, but also simplifies installation of the television receiver and facilitates the adoption of a universal television receiver connector.
As indicated above, a television receiver having a single input terminal can easily be connected to a CATV cable. In addition, where an integrated UHF/VHF antenna is utilized, the twin lead antenna cable could be terminated in a coaxial-type connector for interfacing with the single input terminal of the television receiver. However, where separate UHF and VHF antennas with associated, respective antenna leads coupled thereto are employed, an antenna coupler for interfacing with a single input terminal on the television receiver is currently not available. In particular, because of the continued widespread use of the "rabbit ears"-type of VHF antenna mounted on the television receiver and the "bow tie"-type of UHF antenna, there is a requirement for an antenna coupler capable of providing UHF and VHF signals via separate input leads to a single input terminal of a television receiver.
Therefore, the present invention provides a UHF/VHF splitter-balun assembly capable of coupling a pair of UHF and VHF antenna twin lead conductors to a single input terminal of a television receiver.